Income Taxes - Tax Effects of Temporary Differences That Give Rise to Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Accrued liabilities not currently deductible	$ 3,454	$ 2,305
Intangible assets—excess of tax basis over financial statement basis	45,138	54,647
Indirect federal impact of deferred state taxes	(4,518)	(3,198)
Deferred revenue		165
Net operating losses	50,038	35,814
Stock-based compensation	2,565	5,783
Other	203	(56)
Gross deferred tax assets	96,880	95,460
Deferred tax liabilities:
Intangible assets—excess of financial statement basis over tax basis	(1,751)	(1,245)
Property and equipment	(2,251)	(5,739)
Gross deferred tax liabilities	(4,002)	(6,984)
Valuation allowance	(92,878)	(88,476)
Current	551	334
Non-current	$ (551)	$ (334)